i said "jesus", which is whom christianity is supposed to follow all of its principles after

He did preach about marriage of a man and his wife, specifically. Never said it was even remotely OK for it to be man and man or girl and girl. Also, in Leviticus, which were laws that were upheld, with some exceptions, homosexuality is forbidden. Jesus did, however, forbid things such as stoning, saying that more or less, it was up to God, who was without sin and all good to decide their fate.

Jesus didn't say anything bad about homosexuality. And you can't choose to follow one of Leviticus' words and ignore the rest, it doesn't work that way.

You're right, it doesn't. Many of the cleanliness laws in Leviticus were declared invalid in the New Testament, something like "do not cleanse what I have made clean" was the terminology. Following this, clarification was given that it referred to things like eating meats, cleaning the hands, wearing fabrics, etc. and the things like sex and marriage, which had been raised to a sacramental level, were still under the basic provision of one-man, one-woman.

there's a lot of things he never said were okay, though :P and didn't jesus say that he came to replace the old laws, or something like that?

oh.. thaanks.

He came to fulfil, which somehow also means they became invalid, despite him saying otherwise. Sorry, cbf looking up actual passages for you.

To clarify that, it has to do with the fulfillment of Isaiah's prophecy (which was concerning the Messiah, ie Jesus). According to Isaiah, the fulfillment would mark the beginning of a new Earth and Heaven. Jesus said that none of the laws (Mosaic Law) would be abolished until the Earth and Heaven passed away. After His death and resurrection, the prophecy was fulfilled and the old laws passed away. You'll hear this referred to as the New Covenant.

thaaanks